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Black holes have a fearsome reputation that's only partly justified. The maw of a black hole is indeed a potentially destructive thing, but most matter—including gas stripped from nearby stars—is not destined to end inside the black hole. Instead, a lot of it ends orbiting the black hole, and the energy that's released by the material that is getting swallowed blasts a lot of material back out into space. So, black holes don't simply devour every object that comes near them.

All of this makes a new observation particularly interesting. Astronomers M. Nikołajuk and R. Walter caught a black hole in the act of destroying and consuming part of a large planet or small brown dwarf. This event involved a supermassive black hole located in a relatively nearby galaxy, and emitted a burst of intense X-ray light that fluctuated over a short time span, then faded. The flare and its aftermath behaved as expected if the black hole disrupted an object at least 14 times Jupiter's mass, then consumed about 10 percent of the gas that once was part of the object.

In 2011, astronomers using the INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory) gamma ray telescope discovered a strong source of emissions coming from the galaxy NGC 4845. Follow-up observations using INTEGRAL along with other gamma- and X-ray telescopes confirmed the flare was located within the central region of the galaxy, where the supermassive black hole resides.

Typically, as matter falls onto a black hole at the center of a galaxy, it forms an accretion disk, a rotating region of material that heats to very high temperatures. The result is often strong emissions in gamma rays and radio light, with the output fluctuating only slightly.

However, the subsequent observations of NGC 4845 found the emissions fluctuated by a huge amount over a matter of days. After the light emission peaked, they faded over the course of a year, behavior very unusual for a supermassive black hole. The researchers suspected a one-time event, rather than the normal, steady diet of most black holes.

The authors used calculations of energy output and the measured variation of light emissions to work backward to what could have produced the burst. They found a relatively small amount of mass could do the trick, provided it hit the black hole fairly quickly. This mass would be the equivalent to about 10 percent of the mass of either a very large planet or small brown dwarf, anywhere between 14 and 30 times the mass of Jupiter.

(Brown dwarfs are star-like objects with insufficient mass to start hydrogen fusion in their cores. There is sufficient overlap between large planets and small brown dwarfs that it's hard to distinguish between them, but let's say the black hole ate a planet because that's more fun.)

The researchers compared this scenario to other possible explanations for the flare, including the possibility of a small star coming close to the black hole, or a brief window opening in the shroud of gas surrounding the black hole. They concluded the planet or brown dwarf was a more likely result, based on the specific behavior observed.

In the scenario proposed in the new paper, the super-Jupiter drifted close to the supermassive black hole in NGC 4845. The gravitational attraction on the near side of the planet was stronger than on the far side, pulling it out of shape. (This is known as the tidal force, and it is responsible for the twice-daily tides on Earth.) At some point, the internal force of gravity holding the planet together was insufficient to keep the black hole from ripping about 10 percent of the mass off in one burst.

This matter fell onto the black hole, creating a particularly bright but fluctuating accretion disk. It also made a corona-like cloud around the black hole, the first event of its kind ever observed. Some of the disrupted material eventually returned to the planet, while some was eventually swallowed by the black hole. As the planet moved away, there was a gradual fading of the light emissions, consistent with the data.

Such tidal disruptions are rare events, with perhaps one occurring in a million years' time for a given galaxy. However, there are a lot of rogue planets drifting around, unattached to any star, so the authors suggest that planet disruptions might be at least as common as stars being disrupted. With all the supermassive black holes in all the galaxies in the Universe, the chances of seeing another planet-munching black hole are pretty good, if we know what we're looking for.

Get close enough to the black hole? Sure. Eventually gravity even breaks subatomic particles apart into the kind of degenerate matter believed to be at the heart of neutron stars. I don't think that kind of degeneracy is observed on this side of an event horizon though, but I'll leave it to the pros to correct me.

Computer simulation my foot, I can see it's Aurich putting together a picture of bubbles from his tropical fish tank at night, an amoeba, a cirrus spissatus rotated 90° and a smoke ring from his briar pipe!

Thirty or so years ago, I listened to my dad's stories about stars and planets and supernovae, eyes wide, mouth agap.... .... twenty years ago, I was amazed while visiting the local city's observatory and watching the planets through an impressive 3 m telescope.

Today, I marvel at how far we have come. It's beyond amazing. We truely live in interesting times.

Thanks for the story and congrats to all the researchers doing this stuff...

Brown dwarfs are star-like objects with insufficient mass to start hydrogen fusion in their cores. There is sufficient overlap between large planets and small brown dwarfs that it's hard to distinguish between them, but let's say the black hole ate a planet because that's more fun.

Apparently something similar might be visible in our own galaxy this year as the central black hole devours a passing gas cloud. Given that NGC 4845 is 47 million ly away, this must have been a pretty dramatic event, so we might get something visible with low-power lenses.

Yeah why not, you can say that again. I guess it is appropriated to described it this way after all what happened to it. When all the gas on board got sucked away by this black hole, what it had left on that planet was nothing but a bare bone core. From what was 14 times Jupiter's mass down to the size of our moon? Or maybe less. Poor little guy.

Get close enough to the black hole? Sure. Eventually gravity even breaks subatomic particles apart into the kind of degenerate matter believed to be at the heart of neutron stars. I don't think that kind of degeneracy is observed on this side of an event horizon though, but I'll leave it to the pros to correct me.

A normal black hole can be though of a sort of an accelerator that works by random chance, and the closer you get to the event horizon the more concentrated the particles become and the more random chance produces interesting results.

If degeneracy beyond the subatomic occurs outside the event horizon, it occurs infrequently and only at the barest fringe above the horizon.

Stars and planets that orbit these giant black holes get a bit closer with each orbit. Assuming that this was the first time this planet was close enough to get disrupted, it's very possible that during the next swing in its closest approach it will be totally destroyed. This could be just a few years from now. The closest objects orbiting massive black holes are moving at a large percentage of the speed of light because of their close approach. It should be a lot more spectacular than this event was.